Joint replacement surgery is quite common and it enables many individuals to function properly when otherwise it would not be possible to do so. Such patients of joint replacement surgery typically suffer from osteoarthritis or rheumatoid arthritis. Artificial joints usually comprise metallic, ceramic and/or plastic components that are fixed to existing bone.
Such joint replacement surgery is otherwise known as total joint arthroplasty. Total joint arthroplasty is a well known surgical procedure by which a diseased and/or damaged joint is replaced with a prosthetic joint. In a typical total joint arthroplasty, the ends or distal portions of the portion of the bone adjacent the joint are resected or a portion of the distal part of the bone is removed and the artificial joint is secured thereto. Often, particularly in knee and hip total joint arthroplasty, the distal portion of the bone is resected and the medullary canal exposed. The components of the prosthesis often include stems that are fitted into the exposed medullary canal.
Often, and particularly in, for example, knee, shoulder, or ankle total joint arthroplasty, instruments in the form of bone resecting tools are often utilized with guide blocks to provide for accurate bone resection. The joints are positioned frequently with respect to the resected surfaces of the bones and therefore the accuracy of their placement is important. Often, these guide blocks include elongated slots that are utilized to guide an oscillating saw blade.
When sawing through a saw block with an oscillating saw, it is difficult to control the depth of the cut. Fragile soft tissue in the form of, for example, tendons, ligaments, vascular and neurological structures, and muscle surround and are secured to the bone. When utilizing an oscillating saw to resect bone, as the saw penetrates completely through the bone, the force required to cut through the hard bone may cause the saw to lunge forward toward the soft tissue. The protection of the tendons, ligaments, and muscles adjacent the bone when the oscillating saw is exiting the bone is crucial.
Marks have been placed on the saw blades to assist in the controlling of the depth of the cut when using an oscillating saw. For example, blade manufactures have put marks such as position indicators in the form of scales on their products to give their users a visual representation of how deep they are cutting. Such scales do not actually stop the blade from cutting too deep and damaging soft tissue, ligaments or tendons.
The use of oscillating saws with cutting blocks having elongated slots are widely used in total joint arthroplasty. Such combinations of oscillating saws and cutting blocks are frequently used in total knee arthroplasty and, for example, in total ankle arthroplasty.
An example of the situation of making a cut utilizing an oscillating saw in a cutting block is the surgical procedure for the DePuy Agility™ ankle tibial component. Before the Agility™ ankle tibial component may be inserted, the distal end of the tibia and fibula must be resected. This resection is done through an anterior approach through a mounted saw block. On the opposite side of the tibia and fibula are a neurovascular bundle and the Achilles tendon. A need therefore remains for an invention to control the depth of an oscillating saw when resecting bone, particularly for use in knee and ankle arthroplasty.